The momentum of a body is the quantity of motion in the body, and is the product of the mass and the speed.

As an example: To find the momentum of a body 9 lbs. in weight, moving with a velocity of 75 ft. per second, the rule is:

We may abbreviate this rule by substituting letters for quantities. Let the mass be represented by M and velocity by V. Then

Momentum = M X V

The multiplication sign is usually left out between letters; therefore the quantity is written MV. Momentum may be expressed as a product of pounds by feet per second and tons by feet per second. In the metric standard it may be expressed as a product of grams by centimeters per second, or kilograms by centimeters per second.